1. Technical Field
This invention relates to a data processing apparatus, a data processing method, and computer readable medium that storages a data processing program for erasing data having a plurality of data areas.
2. Related Art
In recent years, a hard disk as a storage medium for retaining image data, etc., has been used in a copier, a printer, etc.; however, retained information in the discarded hard disk may be left. Thus, the necessity for erasing unnecessary information in the hard disk grows and a large number of techniques are disclosed as for information erasion techniques in hard disk. National Security Agency (NSA) recommendation method (overwrite with random numbers at the first and second times and overwrite with fixed values at the third time) is generally known as a data erasion method in hard disk. As another method, a method of increasing the number of overwrite times to more enhance the erasion effect is generally known.